Liquid conductor heater



June 13, 1933. M. w. HANKS 1,913,442

LIQUID CONDUCTOR HEATER Filed Feb. 2'7, 1930 mum-w IIIIIIII u- 18 H 1\fij j Patented June 13, 1933 PATENT OFFICE MARSHALL W. BANKS, OFMADISON, WISCONSIN LIQUID CONDUCTOR HEATER Application filed February27, 1930. Serial No. 431,711.

This invention relates to improvements in liquid conductor heaters inwhich heat is generated by the passage of an electric current through abody of liquid in which fi' spaced electrodes are partially or whollysubmerged. Heaters of this type are described and claimed in several ofmy prior patents and, for illustration, in the United States patent toMarshall W. Hanks and Max Mason No. 1,683,071 granted September 4, 1928.

Liquid conductor heaters may be advantageously employed for heating orcooking various articles or commodities such as eggs or other foodproducts, the sterilization of instruments, and other uses. For mostpurposes, it is desirable that a measured quantity of liquid be placedin the vessel containing the electrodes between which the current passesso that the apparatus has a definite time period of operation determinedby the time required to effect a complete evaporation of the liquid anda consequent shut-off of the current flow. Since many liquid conductorheaters, particularly those employed for heating and cooking purposes inthe household, are commonly operated by persons who are not highlyskilled in the operation of electric apparatus, it is desirable so thatsuch forms of apparatus be so constructed as to protect the operator, asfar as possible, from the danger of shock by reason of contact of thefingers or other parts ofthe body with the electrodes or the liquidthrough which the current passes.

The principal object of the invention is -to provide the vessel, whichcontains the spaced electrodes and in which the liquid conductor isadapted to be contained, with an insulating device which prevents thehands of the operator from coming accidentally into contact with theelectrodes or with the liquid conductor by which they are connected. Afurther object is to provide the vessel of a liquid conductor heaterwith an insulating partition by which the chamber is divided into anelectrode containing chamber and another chamber adapted to contain theobject or objects to be heated. Another object of the invention is toprovide a liquid conductor heater comprising a vessel containing spacedelectrodes and having mounted therein an insulating device which notonly prevents contact of the operator with these electrodes but alsoserves as a support for the oblect to be heated or cooked. A furtherobject is to provide the vessel of a liquid conductor heater with aremovable insulating tray which is perforated to permit the escape ofvapor from the space occupied by the electrodes but which preventsaccidental contact of the hands of the operator with the electrodes.Other objects relate to various features of construction and arrangementwhich will appear more fully hereinafter.

The nature of the invention will be understood from the followingspecification taken with the accompanying drawing, in which twoembodiments are illustrated. In the drawing,

Fig. 1 shows a central vertical section taken through a liquid conductorheater embodying the features of the present invention and adaptedparticularly for use in cooking eggs;

Fig. 2 shows a horizontal section taken on the line 22 of Fig. 1;

Fig. 3 shows a top plan view of the base of thei1 heater with the coverand eggs removed; an

Fig. 4 shows a central vertical section through a modified form ofconstruction adapted for use, for example, in heating a babys milkbottle.

The form of the invention shown in Figs. 1, 2 and '3 comprises a vessel10 formed of porcelain or other suitable insulating material and havinga downwardly and outwardly flared base flange 11 which is adapted torest upon a table or other support 12. Mounted in the lower part of thevessel 10 is an electrode 13 in the form of an annular metal ring seatedon the bottom of the vessel around a central upwardly extendingprojection 14 formed integrally with the bottom of the vessel. A pair ofthreaded posts 15 are secured to the under side of the electrode 13 andextend downwardly through apertures in the bottom wall of the vessel,being engaged at their lower ends by nuts '15. These posts are adaptedto have a fluid-tight connection with the apertures through which theypass in order to prevent the escape of fluid from the interior of thevessel. Mounted centrally in the bottom of the vessel and extendingupwardly through the projection 14 is a threaded post 16 which has athreaded connection at its upper end with the central hub portion 17 ofanother electrode 17 This electrode is provided with a plurality ofperforations 1,7 which are distributed over its surface, as shown inFig. 2, and it is spaced upwardly from the lower electrode 13 with theouter edge thereof engaging an annular shoulder 18 formed on the innerwall of the vessel 10. The threaded post 16 has a threaded extension 19of reduced diameter which is engaged at its lower end by a threaded nut19? of insulating material. An electric conductor 20 is connected to oneof the posts 15 beneath one of the nuts 15 and another conductor 21,leading from the other side of the circuit, is electrically connected tothe mem-. ber 19 by means of a nut 22 which threadedly engages themember 19 beneath the bottom of the vessel. The conductors 20 and 21have a common insulating covering 23 and are extended outwardly throughan aperture 24 in the base flange 11. A cover plate 25 is seated againstan annular shoulder 26 formed on the base flange 11 and is held in placeby the engagement thereof with the reduced upper portion of theinsulating nut 19 thus enclosing the terminal posts and electricalconductors in the chamber which is thus formed within the base flange.

lVhen a liquid conductor, such as water, is placed in the vessel 10, aconnection is thereby established between the spaced electrodes 13 and17 so that the current flowing through the liquid vaporizes it andcauses the vapor to pass upwardly to heat any object which may be placedin the chamber formed by the upper part of the vessel 10 and thecomplementary dome-shaped cover 30, which may be formed of metal orinsulated material and arranged to have its lower edge seat upon theshoulder 31 around the upper edge of the vessel within the annularshoulder 32 formed thereon. The cover 30 is preferably provided with oneor more apertures 23 which permit the escape of steam or vapor from theheating chamber and the upper part of the cover may be provided with ameasuring vessel 35 formed of porcelain, bakelite, or other insulatingmaterial, so that it may serve also as a handle for the cover. Thechamber 35 of this measuring vessel is adapted to receive a-measurcdquantity of liquid and this measured quantity of liquid flows graduallydownward through the reduced opening 36 to the lower part of the vessel10 where it establishes the connection between the electrodes,

as referred to above. By the use of this measuring chamber having arestricted outlet, the liquid is gradually supplied to the vessel sothat a rapid rise of current, when the apparatus is started inoperation, is prevented, as more'fully set forth and claimed in my priorlgatent No. 1,683,070, dated September 4, 1'. 28.

The vessel 10 is provided some distance above the upper electrode 17with an annular shoulder 37 which serves as a support for a removabletray 38 formed of insulating material such as porcelain, moldedbakelite, and the like. This tray, which may be concave or convex tofacilitate drainage, is adapted to fit the cylindrical wall 39 whichextends upwardly from the shoulder 37 which may be formed as a series ofprojecting lugs, and it is provided with a number of apertures 40through which the steam or vapor may escape from the chamber 41immediately above the electrodes to the heating chamber 42 formed by theupper part of the vessel 10 and the cover 30, within which the object orthings to be heated are placed. The tray 38, which thus serves as apartition to divide the space within the vessel into two separatechambers, also serves preferably as a support for the eggs 43 or otherobjects to be heated and for this purpose the tray has formed integrallytherewith a plurality of downwardly concave receptacles 44 which areadapted to engage the lower ends of the eggs. This partition or tray 38,in addition to providing a support for the eggs, serves as an insulatingdevice to prevent accidental contactofthe fingers of the operator withthe electrode 17 or with the damp walls of the chamber 41 and therebyeliminates the danger of shock. The apertures 40 through this partitionor tray are of such small size that the fingers cannot be insertedtherethrough and although the tray may be intentionally removed, itsengagement with the annular' shoulder 37 and substantially close fitwithin the cylindrical wall 39 will prevent its accidental removal.During the operation of the device, the liquid is vaporized by thepassage of the current and the resulting vapor passes upwardly throughthe passages 40 to heat and cook the eggs 43 in the heating chamber 42.This operation continues until the liquid is entirely vaporized, whenthe special form of electrodes herein illustrated are adapted to effecta rapid shut-oil of the current flow, as described and claimed in theprior Patent No. 1,683,069.

In the embodiment illustrated in Figs. 1, 2 and 3, the principalelectrode 17 has a screwthreaded engagement with the post 16 and, ifdesired, the tray 38 may be provided with legs 45, as shown by dottedlines in Fi 1, for connecting it with the upper electr e so that thetray can be removed only by a rotative movement which willsimultaneously remove the upper electrode from its engagement with thepost 16. The upper electrode 17, whether it is connected to the tray 38or Inn III

not, referably contacts with the annular shoul er 18 on the vessel 10when it is-in its lower position, a feature which is adapted toeliminate or greatly reduce the danger of shock through contact with thedam walls of the vessel, as described and claim in my co-pendingapplication Serial No. 431,712, filed February 27, 1930.

In Fig. 4 of the drawing, there is illustrated somewhat diagrammaticallya modified form of the invention. This modified form comprises a vesselformed of porcelain or other suitable insulating material which has anoutwardly flared annular base flange 51 adapted to rest upon a support.One plate electrode 52 is mounted on the bottom of the vessel and isconnected to a conductor 53 leading upwardly through the bottom wall. IAnother plate electrode 54 is spaced upwardly from the electrode 52 andconnected to another conductor 55 forming the other side of the electriccircuit and also extending upwardly through the base of the vessel.Seated directly on the upper electrode 54, which may be supported by acentral insulating post 56 or by other means, is an insulating tray orplate 57 havinglegs 58 which rest directly upon the upper electrode.This tray serves as a partition to prevent accidental contactvwith theupper electrode with the hands of the operator and it is curved toconform to,the curvature of the bottom of a babys milk bottle 58, for

35 example, which is placed thereon and which is adapted to be heated bythe vapor passing upwardly from the region between the gl7ectrodesaround the outer edges of the tray 0 Although two forms of the inventionhave been shown and described by way of illustration, it will beunderstood that it may be constructed in various other embodimentswithin the scope of the appended claim. 5 I claim:

A liquid conductor heater comprising a vessel adapted to contain aliquid conductor, a pair of spaced electrodes mounted in the lower partof said vessel to be connected by 50 said liquid conductor, and aninsulating partition extending across said vessel above said electrodesand having formed therein a plurality of downwardly concaved perforatedreceptacles adapted to conform to portions of $8 the articles to beheated.

In testimony whereof, I have subscribed my name.

MARSHALL W. HANKS.

